http://www.abc.net.au/science/news/stories/s1222754.htm
Oz desert best to photograph fireballs Heather Catchpole Australian Broadcasting Corporation Science Online October 19, 2004 The Australian desert is the perfect place for a crafty camera system that automatically captures the trails of meteors as they shoot across the sky, says an international team of scientists. U.K. researcher Dr Philip Bland from Imperial College London published the team's results in the current issue of the journal Astronomy & Geophysics. Bland and team are from the Desert Fireball Network, which includes scientists from the U.K., Czech Republic and Australia. Like other fireball networks since the 1950s, the researchers attempt to track the orbit of meteors and collect meteorites that fall to Earth. But only four meteorites have ever been recovered from meteors whose trails have been photographed, Bland said. The Desert Fireball Network has built and tested a Czech-built, prototype camera that automatically takes photographs of the sky, the first autonomous camera to be used this way. Humans are needed only to change the camera's film and batteries, which over one year of testing experienced lightning, dust storms and 45ºC heat. Lovely spot for a camera The researchers looked at deserts around the world for the perfect place to put the camera. Bland said this was the Nullarbor Plain, which stretches about 1200 kilometres across Western Australia and South Australia. Team member Dr Alex Bevan, curator of mineralogy and meteoritics at the Western Australian Museum in Perth, said the surface of the Nullarbor is about 35,000 years old, and is dry most of the time. "There's a lack of vegetation, and pale limestone makes the meteorites easy to spot," Bevan told ABC Science Online. The team aim to put another two autonomous cameras on the Nullarbor with the prototype. The extra cameras are needed to triangulate the positions of the meteors as they streak across the sky. "Eventually we hope to have five cameras to increase the area of sky covered," he said. Monitoring meteors The photographs give accurate measurements of the velocity, start point and end point of meteors as they burn up in the Earth's atmosphere, Bevan said. "If you can calculate the velocity of the meteor relative to the Earth, you can get the velocity relative to the Sun and calculate its orbit. "It also gives us an idea where to look on the ground." Bevan said they hope to double the number of meteorites discovered within a few years. "The more meteor orbits you know, the more likely you are to pin the source of the meteors down to a particular object in the asteroid belt," he said. He said currently the U.S. and Japan were spending millions of dollars trying to sample asteroids within the asteroid belt between Mars and Jupiter. The Australian cameras would allow scientist to better predict where the meteors came from and pinpoint certain asteroids, he said. "You can say this asteroid is interesting, go and look at this." Bland said scientists have built most fireball networks in their own countries. Australia, for example, has had its own network before, but not on this scale and not with this sophistication. And in Europe, networks have taken photos of hundreds of meteors, but the meteorites themselves often end up lost in the vegetation. ______________________________________________ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list